Tumorigenic and metastatic abilities of FL, transformed human amnion, Vero and LLC-MK-2, continuous monkey cell lines (CCLs), none of which produced lung metastasis in nude mice, were studied in ATG-treated newborn Wiistar rats. Effects of subcutaneous (sc) and intraperitoneal (ip) inoculation of 10(6) and 10(7) cell were compared. Increased sensitivity of the rat system was achieved by larger size of the sc inoculum or the ip route of inoculation. This highly sensitive assay is especially important for evaluation of possible metastatic abilities of CCLs as substrates for vaccine production. The data were presented at the 15th International Cancer Congress in 1990 and published in Biologicals (formerly the Journal of Biological Standardization) in 1991. This project has been completed.